Wednesday, July 22, 2015

Latest ENSO report - El Niño is getting stronger

The latest ENSO wrap up from the Australian Bureau of Meteorology indicates that the El Niño is likely to continue to strengthen, with trade winds weakened or reversing.

The 2015 El Niño continues to develop. Weakened (or reversed) trade winds have resulted in further warming over much of the tropical Pacific Ocean. All key ENSO ocean monitoring areas have been more than 1°C above average for 10 successive weeks—two weeks longer than the record in 1997. The eastern tropical Pacific is now at or exceeding +2°C. In the atmosphere, the past week has seen the Southern Oscillation Index (SOI) drop to around -20, the lowest values of the event so far.

Warning to the bandwidth challenged - one of the files below the fold is rather large (just under 1 MB).

The model outlook from BoM shows the likely strengthening of El Nino, with not that much of a spread between models:

Next an animation of sub-surface temperatures in the equatorial Pacific, down to 400m, starting in January 2014 through to June 2015. This year is different to last year. These are from BoM.

Here's an animation of sea surface temperatures across the Pacific, from NOAA images from January this year through to 20 July:

Below is the latest image of sea surface temperature anomalies in the Pacific, with markups (by me not NOAA). Hot spots are popping up all over:

The Central Pacific has had three typhoons prior to 17 July this year .. that date is the earliest that ANY typhoon had occurred in any other seasons since the 1950s.

The North Pacific ACE (Accumulated Cyclone Energy) is 30% higher for this time of year than at any other time since 1971 (when calculations can be started)

Wind shear, dust and surface pressures over the Atlantic are anomalously high, with relatively cold SSTs, and consequently the Atlantic hurricane season could be significantly curtailed this year, at least for the beginning and middle parts.

The NCEP discussion stated that the Atlantic season would be less active and that the Pacific season more active as a result of El Nino, so this is not really a surprise, it is part of the usual pattern.

The NCEP discussion does cover El Nino impacts. However, in addition to this the Saharan dust loads are notably high (probably associated with a negative AMM). This suggests that the Atlantic season could be at the lower end of the already low expectations. Emphasis on "could".

This may be slightly off topic, sorry for that.. Then again, droughts and El Nino may sometimes be linked..

Anyways, there is a recent publication "Variability and trends in global drought" investigating drought in general - and deniersphere has taken it as an evidence that once again climate science gets it wrong. No increase in droughts as predicted..

http://onlinelibrary.wiley.com/doi/10.1002/2015EA000100/full

A couple of things nag me here..

The paper is out this year but uses data up to 2009 - why not up to 2014 (or 2013)?

Spot check on California: Their results show no change in droughts.. Then again (eye balling only, sorry) noaa indices seem to suggest increase trend in droughts..

https://www.ncdc.noaa.gov/sotc/drought/201506#det-reg-spei

They are using different indices so that could be a natural reason.. But.. Am I over interpreting / misunderstanding this - or is what is going on..?

I've just skimmed the paper. Their definition of %drought is "The percent of the global land area with annual sums of PMPE less than zero". Where PMPE is monthly precipitation (P) minus potential evapotranspiration (PET).

So while they found no change in total land area under drought, it says nothing about the severity of drought. (Some science points to dry areas getting drier and wet areas getting wetter - so that wouldn't conflict with what this paper found.)

It also seems to have drought computed by another method that shows it to have increased.

What the authors are saying is that the increased rain as the world warms, counteracts the increase in evapotranspiration. I don't know how valid that is - or how valuable it is to combine all land areas to get a global average.

That's the sort of thing that Roger Pielke Jr does to argue that it's not getting any wetter or drier in the USA - even though the east is getting wetter and the west is getting drier. Roger just averages over the lot to make out that nothing's changed. I'm not saying that's all this paper has done though.

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All you need to know about WUWT

WUWT insider Willis Eschenbach tells you all you need to know about Anthony Watts and his blog, WattsUpWithThat (WUWT). As part of his scathing commentary, Wondering Willis accuses Anthony Watts of being clueless about the blog articles he posts. To paraphrase:

Even if Anthony had a year to analyze and dissect each piece...(he couldn't tell if it would)... stand the harsh light of public exposure.

Definition of Denier (Oxford): A person who denies something, especially someone who refuses to admit the truth of a concept or proposition that is supported by the majority of scientific or historical evidence.
‘a prominent denier of global warming’
‘a climate change denier’

Alternative definition: A former French coin, equal to one twelfth of a Sou, which was withdrawn in the 19th century. Oxford. (The denier has since resurfaced with reduced value.)